Papers by Author: Je Wook Chae

Abstract: On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The muscle-skeleton model was developed by the finite element method using beam and spar elements. In this study, a structural analysis has been performed in order to investigate the human body impact by firing a 5.56mm small caliber machine gun. The firing experiments with a standing shooting posture were performed to verify analytical results. The result of this study shows analytical displacements of the human-rifle system and experimental displacements of real firing. In the results, the analytical displacement on the human body is presented.

Abstract: In the conventional weapon system, such as gun and small arms, it is a general trend that for maximization of its performance and enhancement of its effectiveness, the fire control system; FCS is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst ammunition is developed in parallel for the maximization of effectiveness. Since setting fuse of the flight time for the air burst ammunition is adapted for next rifle, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy. This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

Abstract: The hit rate is affected by the shooting impact of the human-rifle system. The impact response of the human-rifle system is determined mainly by the geometrical parameters and contact boundary conditions. In this study, the height and weight of the considered human model are 170 cm and 60 kg, as these parameters mirror 50 per cent of Korean males in their twenties. The rifle model is applied on the K-2. The impact path analysis of three typical shooting postures: the standing, kneeling and prone shooting postures is performed with experimental impulse-time history during a shooting test. The biomechanical response such as impact transfer path, force history and displacement history are investigated.

Abstract: This paper includes a study on the surface treatments of the barrel of small arms with an aim at improving resistance of corrosion and wear. The inner surface of the barrel is Cr plated or nitrided to improve the performance under the firing. The endurance test was conducted to compare the wear resistance of standard barrel (the non surface treatment barrel), the Cr plating barrel and the nitriding barrel. The wear resistance is evaluated by inner diameter of the barrel, muzzle velocity and dispersion during the firing. And the salt water immersion test was conducted to estimate the corrosion resistance. As the results of the tests, the Cr plating barrel is superior to the NST barrel and the nitriding barrel in a view of corrosion and wear.

Abstract: This study is launched to get exact bore-sighting value in the process of assembly for XK11. Image processing method with Charged Coupled Device camera is chosen for the Error reduction of bore-sighting. The results of this method by using a CCD camera and the Testing Target Method are described in this paper. After we confirm the performance of the Dual-Barrel Weapon and that of the Firing Control System in the Dual Barrel Weapon System, the bore-sighting which is a part of the process in the system assembly is accomplished. In this process, the position of the barrel is identified by using the Testing Target Method that is an existing bore-sighting method. Then the fixing line of the Firing Control System is checked by a Day-Optical part. The precision of the boresighting is required within 1 mil, however the manual method using the human eyes makes it worse. Therefore CCD camera is installed in the eyepieces. Next, we can get the image of the sighting and the center coordinate values of the laser-pointer from each barrel by image processing method. Required bore-sighting value is calculated from the eccentricity of the center coordinate. Finally, we will plan to adopt this result in the assembly process of XK11.